The present invention relates generally to the field of materials science, and more particularly to an article of manufacture or method of making the same including one or more methods for manufacturing a carbon nanotube or nanofilament structure on a carbon substrate as well as products and/or articles made by such a method.
In one aspect, the present invention includes a method of manufacturing a carbon structure including exposing a carbon fiber substrate to oxygen at a first predetermined temperature; and activating the carbon fiber substrate by exposure to oxygen at a second predetermined temperature. A method can also include depositing a catalyst on the carbon fiber substrate; and exposing the catalyst on the carbon fiber substrate to a hydrocarbon at a third predetermined temperature in order to grow a carbon structure thereon.
In another aspect, the present invention includes a method for generating multiscale carbon-carbon structures including exposing a polyacrylonitrile fiber substrate to oxygen at a temperature ranging between 475 and 525 degrees Celsius; and depositing a palladium nitrate catalyst on the polyacrylonitrile fiber substrate. The method can also include decomposing the nitrate thereby leaving substantially pure palladium particles; and exposing the catalyst on the polyacrylonitrile fiber substrate to a hydrocarbon at a temperature ranging between 525 and 575 degrees Celsius in order to grow a carbon structure thereon, wherein the carbon structure can be of multi- or variable-scale. As described further herein, the substantially pure palladium particles can be between 0.3 and 0.5% of the net weight of the polyacrylonitrile fiber substrate and the hydrocarbon comprises a gas mixture of nitrogen, oxygen and one of acetylene, ethylene or methane.
In another aspect, the present invention includes a method for generating multiscale carbon-carbon structures including exposing a polyacrylonitrile fiber substrate to oxygen at a temperature ranging between 475 and 525 degrees Celsius; and rinsing the polyacrylonitrile fiber substrate in a solvent. The method can further include activating the polyacrylonitrile fiber substrate by exposure to oxygen at a temperature ranging between 500 and 550 degrees Celsius; depositing a palladium catalyst on the polyacrylonitrile fiber substrate, wherein the palladium catalyst can be an aqueous solution comprising palladium nitrate; decomposing the nitrate thereby leaving substantially pure palladium particles of between 0.3% and 0.5% of the net weight of the polyacrylonitrile fiber substrate; and exposing the substantially pure palladium particles on the polyacrylonitrile fiber substrate to a gas including ethylene at a temperature ranging between 525 and 575 degrees Celsius in order to grow a carbon structure thereon.
In other aspects, the present invention can include multi-scale or multi-modal carbon structures grown on carbon substrates at substantially atmospheric pressure and at temperatures below 1000 degrees Celsius. As described in further herein, the methods of the preferred and example embodiments are practicable under relatively benign conditions, including ambient pressures, low temperatures, and with relatively simple, inexpensive and scalable equipment. Other aspects and features of the present invention are described in detail with reference to the following drawings.